A Comparative Study on Vacuum and Air Plasma Sprayed Bioactive Akermanite Coating

Air plasma-sprayed akermanite coating is a new type orthopedic implant coating material with high bonding strength and excellent bioactivity. However, its crystallinity is low which affects its chemical stability. In this study, high crystallinity akermanite coating has been prepared using vacuum plasma spray(VPS) method. VPS akermanite coating possesses improved apatite mineralization ability compared with APS coating. An apatite layer has formed on VPS akermanite coating surface after 6 d of immersion into simulated body fluid(SBF), and the thickness of apatite layer on VPS coating is 4 times thicker than that on APS akermanite coating. The ionic release of VPS coating is significantly lower than that of APS coating, showing improved chemical stability. Furthermore, bone marrow stem cells(BMSCs) adhere to and spread well on the surface of both VPS and APS akermanite coating surface without significant difference. The proliferation rate of BMSCs is significantly higher on VPS and APS akermanite coating surface than on HA coating. Our results suggest that vacuum plasma sprayed(VPS) akermanite coating is more suitable as orthopedic implant material due to its improved bioactivity and chemical stability.